作业帮已知x,y的值满足方程组x+2y=3,x-y=-2,求x/(x-y)²+x²-y²/(x+
来源：学生作业帮 编辑：作业帮 分类：数学作业 时间：2024/05/07 16:39:35
已知x,y的值满足方程组x+2y=3,x-y=-2,求x/(x-y)²+x²-y²/(x+y)²的值
x+2y=3 (1)
x-y=-2 (2)
消去y,(1)+(2)×2得：
x+2x=3-4
3x=-1
x=-1/3
消去x,(1)-(2)得：
2y+y=3+2
3y=5
y=5/3
方程组的解为 x=-1/3,y=5/3
x/(x-y)²+(x²-y²)/(x+y)²
=x/(x-y)²+(x+y)(x-y)/(x+y)²
=x/(x-y)²+(x-y)/(x+y)
=(-1/3)/(-1/3-5/3)²+(-1/3-5/3)/(-1/3+5/3)
=(-1/3)/(-2)²+(-2)/(4/3)
=(-1/3)/4-2×3/4
=-1/12-3/2
=-1/12-18/12
=-19/12
x-y=-2 (2)
消去y,(1)+(2)×2得：
x+2x=3-4
3x=-1
x=-1/3
消去x,(1)-(2)得：
2y+y=3+2
3y=5
y=5/3
方程组的解为 x=-1/3,y=5/3
x/(x-y)²+(x²-y²)/(x+y)²
=x/(x-y)²+(x+y)(x-y)/(x+y)²
=x/(x-y)²+(x-y)/(x+y)
=(-1/3)/(-1/3-5/3)²+(-1/3-5/3)/(-1/3+5/3)
=(-1/3)/(-2)²+(-2)/(4/3)
=(-1/3)/4-2×3/4
=-1/12-3/2
=-1/12-18/12
=-19/12
已知x,y的值满足方程组x+2y=3,x-y=-2,求x/(x-y)²+x²-y²/(x+
已知方程组2x-y=10,x+2y=11,求（2x-y)³-（2x-y）²（x-3y）的值
已知方程组{2x+y=6,x-3y=1,不解方程组,求7y(x-3y)²-(3y-x)²的值.
已知方程组2x+y=6 x-3y=1,求7y（x-3y）²-2（3y-x）³的值
已知方程组{2x+y=6,x-3y=1,求7y(x-3y)²-2(3y-x)³的值.
若x、y满足2x+y=6,x-3y=1,求7y(x-3y)²-2(3y-x)³的值
已知x,y,z满足方程组：4x-5y+2z=o;x+4y-3x=0,求x:y:z的值
已知x、y、z满足方程组：x+y-z=6；y+z-x=2；z+x-y=0 求x、y、z的值
已知xy满足方程组｛x+2y=3,x-y=-2.求x/（x-y）平方乘以x方-y方/x+y+（2x+2/x-y）-2的值
已知非零有理数x,y满足x²-4xy+4y²=0,求x-y/x+y-y-x/x+y的值.
若正数x,y满足x²-y²=2xy,求（x-y)/(x+y)的值
正数x,y满足x²-y²=2xy,求x-y/x+y的值